循环流化床锅炉生物质与煤混烧积灰腐蚀试验

Experimental study on ash deposition and corrosion in a CFB boiler co-firing biomass with coal

将3种不同金属管材样品环的气冷腐蚀探头置于某生物质与煤混烧的75t/h循环流化床(CFB)锅炉尾部烟道低温过热器前,通过空气冷却模拟过热器的管壁温度,获得3种混烧比例工况下(持续时间24h)3种管材的积灰样品。利用扫描电子显微镜分析积灰的理化特性,探讨混烧比例和材料种类对积灰腐蚀的影响规律。结果表明:在测试工况下,样品环迎风面不存在明显积灰现象,而背风面积灰明显,且随着材料的不同而有所不同,但未发现明显腐蚀或金属磨损,表明碱金属含量相对较低的生物质与煤混烧并不会造成严重积灰及腐蚀。

During ash decomposition and corrosion tests in a 75 t/h circulating fluidized bed （CFB） boiler burning coal and biomass, the corrosion probe equipped with three kinds of metal samples was placed in front of the superheater, and the superheater tube wall temperature was simulated with a system of air cooling. Three kinds of metal deposition samples were obtained in operating mode （duration time of 24 hours） with three mixing ratios of coal and biomass. The physicochemical property of the samples was analyzed by SEM-EDX. The results show that, under the testing conditions, no deposition was found at the wind side, and the deposition formed at the lee side was different for different metallic materials. No material loss or significant corrosion was detected. It is proved in this study that depositions at the lee side of the superheater were probably more serious than that at the wind side,and the co-combustion of coal and biomass containing low levels of alkali metal will not cause serious deposition or corrosion and can be applied in industrial production.